Improvement in electrical fire-alarm thermometers



J. H. GUEST.

Thermostat.

I No. 95,796. Patented Oct. 12, 1869.

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Letters Patent No. 95,796, dated October 12, 1869.

IMPROVEMENT IN ELECTRICAL FIRE-ALARM THERMOMETERS.

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern Be it known that I, JOHN H. GUEST, of Brooklyn, in the county of Kings, and State of New York, haveinveuted and made a new and useful Improvement in Electrical Fire-Alarm Thermometers; and I do hereby declare the following to be a full, clear, and exact description of the said invention, reference being bad to the annexed drawing, making pzut of this specificnt-ion, wherein- Figure 1 is a vertical section of said thermometer, as introduced in a ceiling, and

Figure 2 is an inverted plan of the same.

Similar letters denote the same parts.

Thermometers have before been applied in building so that the rise of the same, in case of flre,shall sound an alarm by a magnet. These thermometers have been expensive and not rapid in their operation.

My invention is to furnish a neat, cheap, eflicient, and easily-applied thermometer, and one that will not' be liable to be broken, and that will not be prominently visible, so that several of these thermometers can be applied in the same room, it it is large, and that without attracting particular attention, even if the room is plastered and finished with elaborateness or beauty.

The heat from a fire always rises, hence the thermometer must be applied in the ceiling, and the firealarms heretofore constructed have been objectionable in most ceilings in consequence-of their prominence.

The/nature of my said invention consists in an electrical fire-alarm thermometer, in which the expansionstem is bent oil at rightangles, or nearly so, to an elongated or flattened bulb, and the platina conductors are inserted, one through the glass of the bulb and the other into the expansion-tube.

This construction allows the expansion-tube to be no other support, and the elongated orfiattened bulb is the only thing visible below the ceiling, and the same is in a position to be affect-ed by the heat that may arise from a fire even before the same has spread or warmed the entire room;

In the drawingn represents a portion of the plastering of a ceiling;

b, the elongated bulb; and

c, the expansion-tube, which is short, and adapted to being inserted in the plaster and cemented into place, leaving the bulb slightly projecting below the ceiling, or in a recess therein.

The conductor d, of platina, is introduced through the bulb into the mercury, the glass being melted around the same, and the conductor a is inserted into the expansion-tube, the end being placed in such position relatively to the mercury that the temperature will have to rise to a certainpoiut before the electrical circuit will be completed by the expansion of the mercury.

The conductor 2 is to be secured into the expansion tube by sealing-wax or cement.

This thermometer may be applied to a boarded or wooden ceiling, by inserting the tube 0 into a hole.

What I claim, and desire to secure by Letters Patent, is-

An electrical fire-alarm thermometer, formed with the expansion-tube bent at an angle to the bulb, so

platina condnoting-wires, as and for the purposes set forth.

In witness whereof, I have hereunto set my signature, this 13th day of April, 186).

J. H. GUEST.

\Vitncsses:

Guns. H. SMITH,

plastered into a small hole in the ceiling, and requires Geo. 'l. Prscuxnv.

as to be inserted in the ceiling, and fitted with the 

